This invention relates to a seed treated with a fungal/bacterial antagonist combination. In particular, the invention relates to a seed assembly comprising a fungal/bacterial antagonist combination for controlling plant pathogens.
Early and late season stalk and root rot are major causes of crop loss. A variety of plants are affected, including tomatoes, peppers, turf grass, soybeans, sunflower, wheat and corn. The pathogens that cause these symptoms include fungi of the genera Fusarium, Phythium, Phytophthora and Penicillium. 
One approach to solving the problem of early season damping off of plants is treatment of seeds with fungicides, such as captan, metalaxyl and Maxim. Although these chemicals enhance seed germination and seedling stand by inhibiting the pathogenic ability of Phythium spp. (active in cool, wet soils), they have no activity against the pathogenic fungi that are responsible for late season root and stalk rot.
Fusarium and Penicillium are the pathogens responsible for late season root and stalk rot. These pathogens prefer the warm, dry conditions that occur late in the growing season. There is no chemical or biological fungicide available that addresses the problem of late season root and stalk rot in corn. Currently, the only way to deal with this problem is to periodically rotate to a non-susceptible crop to reduce pathogen numbers. Corn growers can also select hybrids that have better “standability,” but such hybrids usually have lower yields. Unfortunately, the corn varieties with the highest yields are usually those most susceptible to late season root and stalk rot.
Trichoderma is a genus of fungi that contains about 20 species. Synonyms for the genus name include Aleurisma and Sporoderma. Trichoderma virens, which is also called Gliocladium virens, is a member of the genus. The natural habitats of these fungi include soil and plant material. A member of the genus, Trichoderma harzianum KRL-AG2 (ATCC 20847) also known as strain T-22, is used as a biocontrol agent that is applied as a seed or soil treatment or on cuttings and transplants. Strains of the species, Trichoderma virens, have also been used for control of damping off diseases in plants. For example, Trichoderma (Gliocladium) virens Gl-21 is known and commercially available at a reasonable price, and is being marketed under the trademark SoilGuard® 12G (EPA Registration Number: 70051-3 and EPA Establishment Number: 067250-IL-001). It is manufactured by Thermo Trilogy Corporation of Columbia, Md. Other known and commercially available Trichoderma virens strains include those having the following ATCC accession numbers: 10043, 10044, 10045, 13213, 13362, 204067, 204443, 204444, 204445, 20903, 20904, 20906, 24290, 42955, 44327, 44734, 48179, 52045, 52199, 58676, 58677, 58678, 62399, 64271, 74180, 9645, MYA-297, MYA-298, MYA-649 and MYA-650.
Bacillus is a genus of rod-shaped, gram-positive, aerobic or (under some conditions) anaerobic bacteria. Bacillus species are widely found in soil and water and some have been used to control plant diseases, including root rot. Bacillus amyloliquefaciens is a spore-forming member of the genus. Bacillus amyloliquefaciens L.L. Campbell strain F (ATCC 23350) is the type strain for the species. Other known and commercially available Bacillus amyloliquefaciens strains include those having the following ATCC accession numbers: 23842, 23843, 23844, 23845, 31592, 49763, 53495 and BAA-390 (Int. J. Sys. Bacteriol. 37:69-71, 1987; J. Bacteriol. 94:1124-1130, 1967).
In the past, Bacillus amyloliquefaciens was also called Bacillus subtilis var. amyloliquefaciens by some investigators. A protease produced from Bacillus subtilis var. amyloliquefaciens is commonly used as a tenderized for raw meat products. According to the U.S. Environmental Protection Agency (EPA), Bacillus subtilis var. amyloliquefaciens strain FZB24 is a naturally-occurring microorganism and widespread in the environment. Bacillus subtilis var. amyloliquefaciens FZB24 (EPA Registration Number: 72098-5 and EPA Establishment Number: 73386-DEU-001) is known and commercially available at a reasonable price, being marketed under the trademark Taegro® by Earth Bioscience, Inc. of Fairfield, Conn.
Background art biocontrol products have comprised the bacterium Burkholderia cepacia, which is also known as Pseudomonas cepacia. This bacterium has been implicated as a human pathogen. Furthermore, it has little or no shelf life unless refrigerated at 4 degrees Centigrade at a minimum of 20 percent moisture.
The background art is characterized by U.S. Pat. Nos. 4,476,881; 4,489,161; 4,642,131; 4,668,512; 4,678,669; 4,713,342; 4,724,147; 4,748,021; 4,818,530; 4,828,600; 4,877,738; 4,915,944; 4,952,229; 5,047,239; 5,049,379; 5,071,462; 5,068,105; 5,084,272; 5,194,258; 5,238,690; 5,260,213; 5,266,316; 5,273,749; 5,300,127; 5,344,647; 5,401,655; 5,422,107; 5,455,028; 5,409,509; 5,552,138; 5,589,381; 5,614,188; 5,628,144; 5,632,987; 5,645,831; 5,665,354; 5,667,779; 5,695,982; 5,702,701; 5,753,222; 5,852,054; 5,869,042; 5,882,641; 5,882,915; 5,906,818; 5,916,029; 5,919,447; 5,922,603; 5,972,689; 5,974,734; 5,994,117; 5,998,196; 6,015,553; 6,017,525; 6,030,610; 6,033,659; 6,060,051; and 6,103,228.
No single reference and no combination of the references teach the invention disclosed herein. The background art does not teach combinations of microorganisms disclosed herein, combinations that provide a surprising consistency of performance in plant disease control.